Lubricant additive compositions containing thiophosphates and thiophosphate derivatives

ABSTRACT

The invention relates to thiophosphates and derivatives thereof useful as antiwear additive components, lubricant additive compositions and lubricant compositions each comprising such compounds, methods for making and using the same, including methods of lubricating machines and machine parts and methods of extending the useful life of elastomeric seal components of such machines.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No. 15/163,481, filed May 24, 2016, which is a continuation of U.S. application Ser. No. 14/830,719 filed Aug. 19, 2015, the entire contents of which is hereby incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to thiophosphates and derivatives thereof useful as antiwear additive components, lubricant additive compositions and lubricant compositions each comprising such compounds, and methods for making and using the same.

BACKGROUND OF THE INVENTION

Traditionally, anti-wear components of lubricating compositions comprise acidic organophosphates salted with amines and/or metal ions. These components provide good anti-wear protection but other performance attributes can suffer including poor seal durability, reduced oxidative stability, and inadequate corrosion inhibition. Phosphorus- and sulfur-containing compounds are understood to be essential in lubricating fluids to protect surfaces from wear as a result of the extreme pressures encountered by the surfaces. As a result, these fluids have traditionally been harmful to seals (dynamic and static) and yellow metals. In addition, there is increasing pressure from regulatory agencies to remove amines and metal ions from lubricating fluids to decrease the environmental impact of such components. Due to these increasing environmental concerns, the presence of amines and metal ions in antiwear additives is becoming less desirable. Accordingly, there is a need to develop novel antiwear compounds contain little or no amines or metal ions.

BRIEF SUMMARY OF THE INVENTION

In one aspect, the invention relates to a compound of formula (I)

-   -   or a tribologically acceptable salt thereof,     -   wherein A is:

-   -   each R¹ is the same or different and is independently selected         from alkyl, alkenyl, cycloalkyl, cycloalkylalkyl, aryl, and         aralkyl, wherein said aryl and aralkyl are optionally         substituted with one to three substituents each independently         selected from alkyl and alkenyl;     -   each R² and R³ are independently selected from H, alkyl,         alkenyl, cycloalkyl and cycloalkylalkyl;     -   Y is selected from the group consisting of alkyl, alkoxyalkyl,         benzyl, and —R⁴—R⁵—R⁶;     -   R⁴ is alkylene;     -   R⁵ is selected from the group consisting of a bond, alkylene;         —C(O)— and —C(R⁷)—;     -   R⁶ is selected from the group consisting of alkyl, hydroxyalkyl,         hydroxyalkyleneoxy, hydroxy and alkoxy;     -   R⁷ is hydroxy;     -   m is an integer from 2 to 8;     -   X₁ is R⁸ or Z;     -   X₂ is selected from the group consisting of R⁸,

-   -   R⁸ is alkyl, alkenyl, cycloalkyl, cycloalkylalkyl, aryl, and         aralkyl, wherein said aryl and aralkyl are optionally         substituted with one to three substituents each independently         selected from alkyl and alkenyl; and     -   Z is

-   -   wherein when X₂ is R⁸, X₁ is Z.

In a second aspect, the invention provides a lubricant additive composition comprising the compound of formula (I) and a detergent, wherein the detergent comprises a sulfonate or a phenate.

In a third aspect, the present invention provides a compound prepared by a process comprising:

-   -   i. reacting a first phosphorodithioating agent with a first         epoxide;     -   ii. reacting the product of step i) with a second         phosphorodithioating agent;     -   iii. reacting the product of step ii) with a second epoxide;     -   iv. reacting the product of step iii) with a third         phosphorodithioating agent; and     -   v. reacting the product of step iv) with a reactive group.

In a fourth aspect, the invention provides a lubricant composition comprising

-   -   a. a compound prepared by a process comprising:         -   i. reacting a first phosphorodithioating agent with a first             epoxide;         -   ii. reacting the product of step i) with a second             phosphorodithioating agent;         -   iii. reacting the product of step ii) with a second epoxide;         -   iv. reacting the product of step iii) with a third             phosphorodithioating agent; and         -   v. reacting the product of step iv) with a reactive group;             and     -   b. a detergent, wherein the detergent comprises a sulfonate or a         phenate.

In a fifth aspect, the invention provides a lubricant composition comprising a major amount of an oil of lubricating viscosity or a grease prepared therefrom and a minor amount of the compound of the present invention.

In as sixth aspect, the invention provides a lubricant composition comprising a major amount of an oil of lubricating viscosity or a grease prepared therefrom and a minor amount of a lubricant additive composition of the present invention.

In a seventh aspect, the invention provides a method of lubricating moving metal surfaces comprising lubricating the metal surfaces with a lubricant composition of the present invention.

In an eighth aspect, the invention provides a method of extending the functional life of an elastomeric seal that contacts a lubricating or functional fluid composition, the method comprising contacting the seal with an effective amount of a lubricating composition of the present invention

DETAILED DESCRIPTION OF THE INVENTION

The invention disclosed herein relates to novel thiophosphate and thiophosphate derivative compounds that are useful as antiwear agents and methods for preparing the same. The invention also provides lubricant additive compositions and lubricant compositions comprising the compounds, and methods of using the same.

The compounds of the present invention include compounds of formula (I)

-   -   or a tribologically acceptable salt thereof,     -   wherein A is:

-   -   each R¹ is the same or different and is independently selected         from alkyl, alkenyl, cycloalkyl, cycloalkylalkyl, aryl, and         aralkyl, wherein said aryl and aralkyl are optionally         substituted with one to three substituents each independently         selected from alkyl and alkenyl;     -   each R² and R³ are independently selected from H, alkyl,         alkenyl, cycloalkyl and cycloalkylalkyl;     -   Y is selected from the group consisting of alkyl, alkoxyalkyl,         benzyl, and —R⁴—R⁵—R⁶;     -   R⁴ is alkylene;     -   R⁵ is selected from the group consisting of a bond, alkylene;         —C(O)— and —C(R⁷)—;     -   R⁶ is selected from the group consisting of alkyl, hydroxyalkyl,         hydroxyalkyleneoxy, hydroxy and alkoxy;     -   R⁷ is hydroxy;     -   m is an integer from 2 to 8;     -   X₁ is R⁸ or Z;     -   X₂ is selected from the group consisting of R⁸,

-   -   R⁸ is alkyl, alkenyl, cycloalkyl, cycloalkylalkyl, aryl, and         aralkyl, wherein said aryl and aralkyl are optionally         substituted with one to three substituents each independently         selected from alkyl and alkenyl; and     -   Z is

-   -   wherein when X₂ is R⁸, X₁ is Z.

In one embodiment, each R¹ is the same or different and is independently selected from C₁-C₃₀alkyl, C₁-C₃₀alkenyl, cycloalkyl, cycloalkylalkyl, aryl and aralkyl, wherein said aryl and aralkyl are optionally substituted with one to three substituents each independently selected from C₁-C₁₀alkyl and C₁-C₁₀alkenyl.

In another embodiment, each R¹ is the same or different and is independently C₃-C₁₀alkyl.

In some embodiments, m is an integer from 2 to 5. In certain embodiments, m is 2.

In one embodiment, each R² and R³ are independently selected from H and C₁-C₁₀alkyl. In another embodiment, for each instance of A, one R² is alkyl and the remaining instances of R² and R³ are H. In a further embodiment, when R² is alkyl, the alkyl is C₁-C₁₀alkyl.

In a further embodiment, X₂ is

In another embodiment, X₂ is R⁸.

In another embodiment, Y is —R⁴—R⁵—R⁶. In a further embodiment, Y is —R⁴—R⁵—R⁶ and R⁴ is alkylene, R⁵ is —C(O)—, and R⁶ is hydroxy or alkoxy.

In one embodiment, R⁸ is C₁-C₁₀ alkyl.

In one embodiment, each R¹ is independently selected from C₁-C₃₀alkyl. In another embodiment, each R¹ is independently selected from C₃-C₁₀ alkyl. In another embodiment, each R¹ is independently selected from C₃-C₆alkyl. In certain embodiments, each R¹ is the same as every other R¹.

In one embodiment, Y is C₁-C₂₀alkyl.

In one embodiment, the invention provides a compound of formula (Ia)

-   -   or a tribologically acceptable salt thereof,     -   each R¹ is the same or different and is independently selected         from alkyl, alkenyl, cycloalkyl, cycloalkylalkyl, aryl, and         aralkyl, wherein said aryl and aralkyl are optionally         substituted with one to three substituents each independently         selected from alkyl and alkenyl;     -   each R² is independently selected from alkyl, alkenyl,         cycloalkyl and cycloalkylalkyl;     -   Y is selected from the group consisting of alkyl, alkoxyalkyl,         benzyl, and —R⁴—R⁵—R⁶;     -   R⁴ is alkylene;     -   R⁵ is selected from the group consisting of a bond, alkylene;         —C(O)— and —C(R⁷)—;     -   R⁶ is selected from the group consisting of alkyl, hydroxyalkyl,         hydroxyalkyleneoxy, hydroxy and alkoxy;     -   R⁷ is hydroxy;     -   X₂ is selected from the group consisting of R⁸,

-   -   R⁸ is alkyl, alkenyl, cycloalkyl, cycloalkylalkyl, aryl, and         aralkyl, wherein said aryl and aralkyl are optionally         substituted with one to three substituents each independently         selected from alkyl and alkenyl; and     -   Z is

In one embodiment, the compound of formula I is selected from:

As used herein, the term “alkyl,” as well as the as the alkyl moieties of other groups referred herein (e.g., alkoxyl) may be a linear or branched chain saturated hydrocarbon containing from 1 to 30 carbon atoms.

As used herein, the term “alkenyl” means a straight or branched hydrocarbon chain containing at least one carbon-carbon double bond. For example, the term “C₂-C₄ alkenyl” means an alkenyl group containing 2-4 carbon atoms. Representative examples of alkenyl include, but are not limited to, ethenyl, 2-propenyl, 2-methyl-2-propenyl, 3-butenyl, 4-pentenyl, 5-hexenyl, 2-heptenyl, 2-methyl-1-heptenyl, and 3-decenyl.

As used herein, the term “substituted” refers to wherein one or more hydrogen atoms are each independently replaced with a non-hydrogen substituent.

As used herein, the term “alkoxy” refers to an alkyl group attached to the parent molecular moiety through an oxygen atom.

As used herein, the term “alkenyloxy” refers to an alkenyl group attached to the parent molecular moiety through an oxygen atom.

As used herein, the term “alkoxyalkyl” refers to a group -alkylene-O-alkyl.

As used herein, the term “alkylene” refers to a methylene or polymethylene group, i.e., —(CH₂)_(z)—, wherein z is a positive integer from 1 to 30.

As used herein, the term “cycloalkyl” means a non-aromatic, monocyclic or polycyclic ring comprising carbon and hydrogen atoms. A cycloalkyl group can have one or more carbon-carbon double bonds in the ring so long as the ring is not rendered aromatic by their presence.

As used herein, the term “cycloalkylalkyl” means a cycloalkyl group that is attached to the parent molecular moiety with an alkylene linker group consisting of at least one carbon.

As used herein the term “hydroxyalkyl” refers to the group R^(a)—R^(b)— wherein R^(a) is HO— and R^(b) is alkylene.

As used herein the term “hydroxyalkyleneoxy” refers to the group R^(a)—R^(b)—R^(c) wherein R^(a) is HO—, R^(b) is alkylene and R^(c) is —O—.

As used herein, the symbol “

” when drawn perpendicularly across a bond indicates a point of attachment of the group. It is noted that the point of attachment is typically only identified in this manner for larger groups in order to assist the reader in rapidly and unambiguously identifying a point of attachment.

As used herein, the phrase “reactive group” refers to an electrophilic chemical group that is capable of attaching a carbon atom of a substituent to a sulfur atom in a nucleophilic P—SH group, for example, in a dithiophosphate, or attaching a carbon atom of a substituent to an oxygen atom of a nucleophilic P—OH, for example, in a phosphate. Such reactive groups are readily recognized by those skilled in the art. Examples of suitable reactive groups in accordance with the present invention include alkyl halides, activated alkyl alcohols including tosylates, triflates and mesylates, epoxides, and acrylate derivatives. In certain embodiments, the reactive group can be selected from 1-bromohexadecane, methyl iodide, benzyl bromide, vinyl butyl ether, ethyl acrylate, 1,2-epoxydodecane, acrylic acid, 1,2-epoxydecane, and 2-hydroxyethyl acrylate.

As used herein, the phrase “phosphorodithioating agent” means a compound with at least one phosphorous atom and two sulfur atoms that can react with a hydroxyl group to form a phosphorodithioate of the structure:

For purpose of the present invention, phosphorodithioating agents include, for example, P₂S₅ and X₂P(S)SH, wherein each X is independently C₂-C₃₀alkoxy or C₂-C₃₀alkenyloxy. Further examples of phosphorodithioating agents in accordance with the present invention include O′,O′-diisopropyl dithiophosphoric acid, O′,O′-di-ethyl dithiophosphoric acid, O′,O′-di-n-propyl dithiophosphoric acid, O′,O′-di-n-butyl dithiophosphoric acid, O′,O′-di-isobutyl dithiophosphoric acid, O′,O′-di-sec-butyl dithiophosphoric acid, O′,O′-di-amyl dithiophosphoric acid and O′,O′-di-hexyl dithiophosphoric acid, or mixtures thereof.

As used herein, the phrase “effective amount” means an amount sufficient to provide the desired effect. For example, the compounds of the present invention are useful as antiwear agents when incorporated into lubricant compositions. Therefore, an effective amount of a compound of the present invention when incorporated into a lubricant composition can be an amount that improves the antiwear properties of the lubricant compositions comprising a compound of the instant invention as compared to the same lubricant composition that does not comprise a compound of the instant invention.

As used herein, the terms “oil composition,” “lubrication composition,” “lubricating composition,” “lubricating oil composition,” “lubricating oil,” “lubricant composition,” “fully formulated lubricant composition,” and “lubricant” are considered synonymous, fully interchangeable terminology referring to the finished lubrication product comprising a major amount of a base oil plus a minor amount of an additive composition. As used herein, the reference to a “major amount” of base oil and a “minor amount” of additive composition means that the lubricating composition contains an amount of base oil that is more than the amount of additive composition on a weight % basis of the total lubricating composition. In certain embodiments, the major amount of base oil is 50-99.999 wt % of the total lubricating composition.

Although many of the compounds of formula I are substantially neutral, the present invention also contemplates base addition salts of compounds of formula I. The chemical bases that may be used as reagents to prepare tribologically acceptable base salts of those compounds of formula I that are acidic in nature are those that form base salts with such compounds. Such base salts include, but are not limited to cations such as alkali metal cations (e.g., potassium and sodium) and alkaline earth metal cations (e.g., calcium and magnesium), ammonium or amine addition salts such as N-methylglucamine-(meglumine), and alkanolammonium and other base salts of tribologically acceptable organic amines, including but not limited to alkylamines such as octylamine and oleylamine. In certain embodiments, the salts of the compounds of formula I are not amine salts.

The phrase “tribologically acceptable salt(s)”, as used herein, unless otherwise indicated, includes salts of acidic or basic groups which may be present in the compounds of the present disclosure. As recognized readily by the skilled artisan, tribology is a term defining a study that deals with the design, friction, wear and lubrication of interacting surfaces in a relative motion (as in bearings or gears). Tribologically acceptable salts are salts that do not negate or interfere with the tribological activity of the compounds. The compounds of the present disclosure that are basic in nature are capable of forming a wide variety of salts with various inorganic and organic acids. The acids that may be used to prepare tribologically acceptable acid addition salts of such basic compounds are those that form acid addition salts, i.e., salts containing tribologically acceptable anions, such as the hydrochloride, hydrobromide, hydroiodide, nitrate, sulfate, bisulfate, phosphate, acid phosphate, isonicotinate, acetate, lactate, salicylate, citrate, acid citrate, tartrate, pantothenate, bitartrate, ascorbate, succinate, maleate, gentisinate, fumarate, gluconate, glucuronate, saccharate, formate, benzoate, glutamate, methanesulfonate, ethanesulfonate, benzenesulfonate, p-toluenesulfonate and pamoate [i.e., 1,1′-methylene-bis-(2-hydroxy-3-naphthoate)] salts. Compounds of the present disclosure that include a basic moiety, such as an amino group, may form tribologically acceptable salts with various amines, in addition to the acids mentioned above.

The compounds of the present disclosure include all stereoisomers (e.g., cis and trans isomers) and all optical isomers of compounds of Formula I (e.g., R and S enantiomers), certain positional isomers, as well as racemic, diastereomeric and other mixtures of such isomers. Those skilled in the relevant art can readily envision such isomers and the isomers are included within the scope of the present invention.

The compounds and salts of the present disclosure can exist in several tautomeric forms, including the enol and imine form, and the keto and enamine form and geometric isomers and mixtures thereof. All such tautomeric forms are included within the scope of the present disclosure. Even though one tautomer may be described, the present disclosure includes all tautomers of the present compounds.

One aspect of the present invention is a compound prepared by a process comprising:

-   -   a. reacting a phosphorodithioate with a first epoxide;     -   b. reacting the product of step a) with a first         phosphorodithioating agent;     -   c. reacting the product of step b) with a second epoxide;     -   d. reacting the product of step c) with a second         phosphorodithioating agent; and     -   e. reacting the product of step d) with a reactive group.

In certain embodiments, the first and second phosphorodithioating agents are each independently selected from the group consisting of P₂S₅ and X₂P(S)SH, wherein each X is independently C₂-C₃₀alkoxy or C₂-C₃₀alkenyloxy. In another embodiment, X₂P(S)SH is O′,O′-dialkyl dithiophosphoric acid. In certain embodiments, the O′,O′-dialkyl dithiophosphoric acid is selected from the group consisting of O′,O′-diisopropyl dithiophosphoric acid, O′,O′-di-ethyl dithiophosphoric acid, O′,O′-di-n-propyl dithiophosphoric acid, O′,O′-di-n-butyl dithiophosphoric acid, O′,O′-di-isobutyl dithiophosphoric acid, O′,O′-di-sec-butyl dithiophosphoric acid, O′,O′-di-amyl dithiophosphoric acid and O′,O′-di-hexyl dithiophosphoric acid, or mixtures thereof.

In one embodiment, the first epoxide and the second epoxide are the same or different. In another embodiment, the first and second epoxide are each independently selected from ethylene oxide and propylene oxide.

The compounds of the present invention are contemplated to be used as an additive in lubricating base oil. As used herein, the term “base oil” refers to oils categorized by the American Petroleum Institute (API) category groups Group I-V oils as well as animal oils, vegetable oils (e.g. castor oil and lard oil), petroleum oils, mineral oils, synthetic oils, and oils derived from coal or shale. The American Petroleum Institute has categorized these different basestock types as follows: Group I, greater than 0.03 wt percent sulfur, and/or less than 90 vol percent saturates, viscosity index between 80 and 120; Group II, less than or equal to 0.03 wt percent sulfur, and greater than or equal to 90 vol percent saturates, viscosity index between 80 and 120; Group III, less than or equal to 0.03 wt percent sulfur, and greater than or equal to 90 vol percent saturates, viscosity index greater than 120; Group IV, all polyalphaolefins. Hydrotreated basestocks and catalytically dewaxed basestocks, because of their low sulfur and aromatics content, generally fall into the Group II and Group III categories. Polyalphaolefins (Group IV basestocks) are synthetic base oils prepared from various alpha olefins and are substantially free of sulfur and aromatics.

Groups I, II, and III are mineral oil process stocks. Group IV base oils contain true synthetic molecular species, which are produced by polymerization of olefinically unsaturated hydrocarbons. Many Group V base oils are also true synthetic products and may include diesters, polyol esters, polyalkylene glycols, alkylated aromatics, polyphosphate esters, polyvinyl ethers, and/or polyphenyl ethers, and the like, but may also be naturally occurring oils, such as vegetable oils. It should be noted that although Group III base oils are derived from mineral oil, the rigorous processing that these fluids undergo causes their physical properties to be very similar to some true synthetics, such as PAOs. Therefore, oils derived from Group III base oils may sometimes be referred to as synthetic fluids in the industry.

The compounds of the present invention can be added to base oils in the form of a mineral oil or synthetic oil, animal oil, vegetable oil, or mixtures thereof. In general, the mineral oils, both paraffinic and naphthenic and mixtures thereof can be employed as lubricating oil or as the grease vehicle. Also contemplated are greases in which any of the foregoing oils are employed as a base.

The compound of the present invention, in addition to other additive components, can be added to a lubricating oil to form a finished fluid having a viscosity of at least an SAE 90 or 75W-85. Viscosity indexes from about 95 to 130 being preferred. The average molecular weights of these oils can range from about 250 to about 800.

Where the lubricant is employed as a grease, the lubricant is generally used in an amount sufficient to balance the total grease composition, after accounting for the desired quantity of the thickening agent, and other additive components included in the grease formulation. A wide variety of materials can be employed as thickening or gelling agents. These can include any of the conventional metal salts or soaps, such as calcium, or lithium stearates or hydroxystearates, which are dispersed in the lubricating vehicle in grease-forming quantities in an amount sufficient to impart to the resulting grease composition the desired consistency. Other thickening agents that can be employed in the grease formulation comprise the non-soap thickeners, such as surface-modified clays and silicas, aryl ureas, calcium complexes and similar materials. In general, grease thickeners can be employed which do not melt or dissolve when used at the required temperature within a particular environment; however, in all other respects, any material which is normally employed for thickening or gelling hydrocarbon fluids for forming greases can be used in the present invention.

Where synthetic oils, or synthetic oils employed as the vehicle for the grease, are desired in preference to mineral oils, or in mixtures of mineral and synthetic oils, various synthetic oils may be used. Typical synthetic oils include polyisobutylenes, polybutenes, polydecenes, siloxanes and silicones (polysiloxanes).

The present invention provides lubricant compositions comprising a major amount of oil of lubricating viscosity or a grease prepared therefrom and a minor amount of a compound of the present invention. The compound of the present invention can be in the lubricant composition in an amount between about 0.001% to 10%, between 0.01% to 5%, between 0.01% to 1.0%, between 0.5% to 2.0%, and between 0.015% to about 0.5% by weight of the total composition. In some embodiments, lubricating compositions can contain between about from 0.01% to 0.5%, between about 0.01 and about 0.4 wt %, or between about 0.01 and about 0.3 wt %, or between about 0.01 and about 0.2 wt %.

As mentioned above, the compounds of the present invention can be readily formulated into lubricant compositions suitable for use with a variety of machine parts and components. The lubricant compositions comprising a compound of the present invention can optionally further comprise one or more other additive components such that the lubricant compositions. The list of additive components disclosed below is not exhaustive and additive components not expressly disclosed herein are well known to the skilled artisan and may also be included in the lubricant compositions. Without limitation, additive components that can be used in the lubricant compositions of the present invention include antioxidants, additional antiwear agents, corrosion inhibitors, detergents, extreme pressure agents, viscosity index improvers, and friction reducers.

In one embodiment, the lubricant composition of the present invention comprises a compound of the present invention and at least one additional additive composition selected from the group consisting of an antioxidant, antiwear agents, corrosion inhibitor, detergent, extreme pressure agent, dispersant, viscosity index improvers, and friction modifiers.

The compounds of the present invention can be incorporated into an oil of lubricating viscosity directly. Alternatively, compounds of the present invention can be prepared in combination with other lubricant additives to form a lubricant additive composition. Generally, the lubricant additive composition will further be incorporated into the oil of lubricating viscosity at a particular wt % of the lubricant additive package relative to the total weight of the final lubricant composition. The wt % selected is generally referred to as the treat rate and the lubricant composition containing the lubricant additive composition is generally referred to as a finished fluid.

In one embodiment the present invention provides a lubricant additive composition comprising a compound of the present invention and at least one additional additive component. The one or more additional additive component(s) can be selected from an antioxidant, antiwear agents, corrosion inhibitor, detergent, extreme pressure agent, viscosity index improvers, and friction modifiers.

Antioxidants

Antioxidant compounds are known and include, for example, phenates, phenate sulfides, sulfurized olefins, phosphosulfurized terpenes, sulfurized esters, aromatic amines, alkylated diphenylamines (e.g., nonyl diphenylamine, di-nonyl diphenylamine, octyl diphenylamine, di-octyl diphenylamine), phenyl-alpha-naphthylamines, alkylated phenyl-alpha-naphthylamines, hindered non-aromatic amines, phenols, hindered phenols, oil-soluble molybdenum compounds, macromolecular antioxidants, or mixtures thereof. A single antioxidant or a combination of two or more can be used.

The hindered phenol antioxidant may contain a secondary butyl and/or a tertiary butyl group as a sterically hindering group. The phenol group may be further substituted with a hydrocarbyl group and/or a bridging group linking to a second aromatic group. Examples of suitable hindered phenol antioxidants include 2,6-di-tert-butylphenol, 4-methyl-2,6-di-tert-butylphenol, 4-ethyl-2,6-di-tert-butylphenol, 4-propyl-2,6-di-tert-butylphenol or 4-butyl-2,6-di-tert-butylphenol, or 4-dodecyl-2,6-di-tert-butylphenol. In an embodiment the hindered phenol antioxidant may be an ester and may include, e.g., an addition product derived from 2,6-di-tert-butylphenol and an alkyl acrylate, wherein the alkyl group may contain about 1 to about 18, or about 2 to about 12, or about 2 to about 8, or about 2 to about 6, or about 4 carbon atoms.

Useful antioxidants may include diarylamines and high molecular weight phenols. In an embodiment, the lubricating oil composition may contain a mixture of a diarylamine and a high molecular weight phenol, such that each antioxidant may be present in an amount sufficient to provide up to about 5%, by weight of the antioxidant, based upon the final weight of the lubricating oil composition. In some embodiments, the antioxidant may be a mixture of about 0.3 to about 1.5% diarylamine and about 0.4 to about 2.5% high molecular weight phenol, by weight, based upon the final weight of the lubricating oil composition.

Examples of suitable olefins that may be sulfurized to form a sulfurized olefin include propylene, butylene, isobutylene, polyisobutylene, pentene, hexene, heptene, octene, nonene, decene, undecene, dodecene, tridecene, tetradecene, pentadecene, hexadecene, heptadecene, octadecene, nonadecene, eicosene or mixtures thereof. In an embodiment, hexadecene, heptadecene, octadecene, nonadecene, eicosene or mixtures thereof and their dimers, trimers and tetramers are especially useful olefins. Alternatively, the olefin may be a Diels-Alder adduct of a diene such as 1,3-butadiene and an unsaturated ester, such as, butylacrylate.

Another class of sulfurized olefin includes sulfurized fatty acids and their esters. The fatty acids are often obtained from vegetable oil or animal oil and typically contain about 4 to about 22 carbon atoms. Examples of suitable fatty acids and their esters include triglycerides, oleic acid, linoleic acid, palmitoleic acid or mixtures thereof. Often, the fatty acids are obtained from lard oil, tall oil, peanut oil, soybean oil, cottonseed oil, sunflower seed oil or mixtures thereof. Fatty acids and/or ester may be mixed with olefins, such as α-olefins.

The one or more antioxidant(s) may be present in ranges of from about 0 wt. % to about 20 wt. %, or about 0.1 wt. % to about 10 wt. %, or about 1 wt. % to about 5 wt. %, of the lubricating composition.

Antiwear Agents

The compounds of the present invention can be used as antiwear agents. However, in certain embodiments, the lubricant additive compositions and the lubricant compositions can contain additional antiwear agent(s). Examples of additional suitable antiwear agents include, but are not limited to, a metal thiophosphate; a metal dialkyldithiophosphate; a phosphoric acid ester or salt thereof; a phosphate ester(s); a phosphite; a phosphorus-containing carboxylic ester, ether, or amide; a sulfurized olefin; thiocarbamate-containing compounds including, thiocarbamate esters, alkylene-coupled thiocarbamates, and bis(S-alkyldithiocarbamyl)disulfides; and mixtures thereof. The phosphorus containing antiwear agents are more fully described in European Patent No. 1490460. The metal in the dialkyl dithio phosphate salts may be an alkali metal, alkaline earth metal, aluminum, lead, tin, molybdenum, manganese, nickel, copper, titanium, or zinc. A useful antiwear agent may be a thiophosphate such as zinc dialkyldithiophosphate.

The additional antiwear agent may be present in ranges of from about 0 wt. % to about 15 wt. %, or about 0.01 wt. % to about 10 wt. %, or about 0.05 wt. % to about 5 wt. %, or about 0.1 wt. % to about 3 wt. % of the total weight of the lubricating composition. In certain embodiments, the additional antiwear agent(s) are in the form of amine salts and present in less than or equal to about 1.0 wt %, less than or equal to about 0.5 wt % or less than or equal to about 0.25 wt %. In other embodiments, the additional antiwear agents are not amine salts.

Detergents

The lubricant composition may optionally comprise one or more neutral, low based, or overbased detergents, and mixtures thereof. Suitable detergent substrates include phenates, sulfur containing phenates, sulfonates, calixarates, salixarates, salicylates, carboxylic acids, phosphorus acids, mono- and/or di-thiophosphoric acids, alkyl phenols, sulfur coupled alkyl phenol compounds and methylene bridged phenols. Suitable detergents and their methods of preparation are described in greater detail in numerous patent publications, including U.S. Pat. No. 7,732,390, and references cited therein.

The detergent substrate may be salted with an alkali or alkaline earth metal such as, but not limited to, calcium, magnesium, potassium, sodium, lithium, barium, or mixtures thereof. In some embodiments, the detergent is free of barium. A suitable detergent may include alkali or alkaline earth metal salts of petroleum sulfonic acids and long chain mono- or di-alkylarylsulfonic acids with the aryl group being one of benzyl, tolyl, and xylyl.

Overbased detergent additives are well known in the art and may be alkali or alkaline earth metal overbased detergent additives. Such detergent additives may be prepared by reacting a metal oxide or metal hydroxide with a substrate and carbon dioxide gas. The substrate is typically an acid, for example, an acid such as an aliphatic substituted sulfonic acid, an aliphatic substituted carboxylic acid, or an aliphatic substituted phenol.

The terminology “overbased” relates to metal salts, such as metal salts of sulfonates, carboxylates, and phenates, wherein the amount of metal present exceeds the stoichiometric amount. Such salts may have a conversion level in excess of 100% (i.e., they may comprise more than 100% of the theoretical amount of metal needed to convert the acid to its “normal,” “neutral” salt). The expression “metal ratio,” often abbreviated as MR, is used to designate the ratio of total chemical equivalents of metal in the overbased salt to chemical equivalents of the metal in a neutral salt according to known chemical reactivity and stoichiometry. In a normal or neutral salt, the metal ratio is one and in an overbased salt, the MR, is greater than one. Such salts are commonly referred to as overbased, hyperbased, or superbased salts and may be salts of organic sulfur acids, carboxylic acids, or phenols.

The overbased detergent may have a metal ratio of from 1.1:1, or from 2:1, or from 4:1, or from 5:1, or from 7:1, or from 10:1.

In some embodiments, a detergent can be used for reducing or preventing rust in a gear, axle, or engine.

In preferred embodiments, one or more detergents can be used to extend the functional life of elastomeric seals when included in the lubricant compositions of the present invention. Suitable detergents for extending the functional life of elastomeric seals include those detergents that comprise a sulfonate or a phenate. Examples of such detergents include overbased or neutral calcium or magnesium sulfonate detergents and overbased or neutral calcium or magnesium phenate detergents.

The detergent may be present at about 0 wt. % to about 10 wt. %, or about 0.1 wt. % to about 8 wt. %, or about 1 wt. % to about 4 wt. %, or greater than about 4 wt. % to about 8 wt. % based on the total weight of the lubricant composition.

Dispersants

The lubricant composition may optionally further comprise one or more dispersants or mixtures thereof. Dispersants are often known as ashless-type dispersants because, prior to mixing in a lubricating oil composition, they do not contain ash-forming metals and they do not normally contribute any ash when added to a lubricant. Ashless-type dispersants are characterized by a polar group attached to a relatively high molecular or weight hydrocarbon chain. Typical ashless dispersants include N-substituted long chain alkenyl succinimides. Examples of N-substituted long chain alkenyl succinimides include polyisobutylene succinimide with number average molecular weight of the polyisobutylene substituent in a range of about 350 to about 5000, or about 500 to about 3000. Succinimide dispersants and their preparation are disclosed, for instance in U.S. Pat. No. 7,897,696 and U.S. Pat. No. 4,234,435. Succinimide dispersants are typically an imide formed from a polyamine, typically a poly(ethyleneamine).

In some embodiments the lubricant composition comprises at least one polyisobutylene succinimide dispersant derived from polyisobutylene with number average molecular weight in the range about 350 to about 5000, or about 500 to about 3000. The polyisobutylene succinimide may be used alone or in combination with other dispersants.

In some embodiments, polyisobutylene (PIB), when included, may have greater than 50 mol %, greater than 60 mol %, greater than 70 mol %, greater than 80 mol %, or greater than 90 mol % content of terminal double bonds. Such a PIB is also referred to as highly reactive PIB (“HR-PIB”). HR-PIB having a number average molecular weight ranging from about 800 to about 5000 is suitable for use in embodiments of the present disclosure. Conventional non-highly reactive PIB typically has less than 50 mol %, less than 40 mol %, less than 30 mol %, less than 20 mol %, or less than 10 mol % content of terminal double bonds.

An HR-PIB having a number average molecular weight ranging from about 900 to about 3000 may be suitable. Such an HR-PIB is commercially available, or can be synthesized by the polymerization of isobutene in the presence of a non-chlorinated catalyst such as boron trifluoride, as described in U.S. Pat. No. 4,152,499 and U.S. Pat. No. 5,739,355. When used in the aforementioned thermal ene reaction, HR-PIB may lead to higher conversion rates in the reaction, as well as lower amounts of sediment formation, due to increased reactivity.

One class of suitable dispersants may be Mannich bases. Mannich bases are materials that are formed by the condensation of a higher molecular weight, alkyl substituted phenol, a polyalkylene polyamine, and an aldehyde such as formaldehyde. Mannich bases are described in more detail in U.S. Pat. No. 3,634,515.

A suitable class of dispersants may be high molecular weight esters or half ester amides.

The dispersants may also be post-treated by conventional methods by reaction with any of a variety of agents. Among these agents are boron, urea, thiourea, dimercaptothiadiazoles, carbon disulfide, aldehydes, ketones, carboxylic acids, hydrocarbon-substituted succinic anhydrides, maleic anhydride, nitriles, epoxides, carbonates, cyclic carbonates, hindered phenolic esters, and phosphorus compounds. U.S. Pat. No. 7,645,726; U.S. Pat. No. 7,214,649; and U.S. Pat. No. 8,048,831 describe some suitable post-treatment methods and post-treated products.

The dispersant, if present, can be used in an amount sufficient to provide up to about 20 wt. %, based upon the total weight of the lubricating oil composition. The amount of the dispersant that can be used may be about 0.1 wt. % to about 15 wt. %, or about 0.1 wt. % to about 10 wt. %, or about 3 wt. % to about 10 wt. %, or about 1 wt. % to about 6 wt. %, or about 7 wt. % to about 12 wt. %, based upon the total weight of the lubricating oil composition. In an embodiment, the lubricating oil composition utilizes a mixed dispersant system.

Extreme Pressure Agents

The lubricating oil compositions herein also may optionally contain one or more extreme pressure agents. Extreme Pressure (EP) agents that are soluble in the oil include sulfur- and chlorosulfur-containing EP agents, chlorinated hydrocarbon EP agents and phosphorus EP agents. Examples of such EP agents include chlorinated waxes; organic sulfides and polysulfides such as dibenzyldisulfide, bis(chlorobenzyl) disulfide, dibutyl tetrasulfide, sulfurized methyl ester of oleic acid, sulfurized alkylphenol, sulfurized dipentene, sulfurized terpene, and sulfurized Diels-Alder adducts; phosphosulfurized hydrocarbons such as the reaction product of phosphorus sulfide with turpentine or methyl oleate; phosphorus esters such as the dihydrocarbyl and trihydrocarbyl phosphites, e.g., dibutyl phosphite, diheptyl phosphite, dicyclohexyl phosphite, pentylphenyl phosphite; dipentylphenyl phosphite, tridecyl phosphite, distearyl phosphite and polypropylene substituted phenyl phosphite; metal thiocarbamates such as zinc dioctyldithiocarbamate and barium heptylphenol diacid; amine salts of alkyl and dialkylphosphoric acids, including, for example, the amine salt of the reaction product of a dialkyldithiophosphoric acid with propylene oxide; and mixtures thereof.

In one embodiment, the organic polysulfides are S-3 enriched organic polysulfides. As used herein, the phrase “S-3 enriched organic polysulfides” refers to organic polysulfides that contain more trisulfide species than mono-sulfide or other polysulfide species. In some embodiments, the S-3 enriched organic polysulfides contain at least 50 wt % trisulfides, or at least 55%, at least 60%, at least 65%, at least 75% or at least 80% trisulfides, with the remaining organic polysulfides being primarily S-2 and S-4 polysulfides. In certain embodiments, the S-3 enriched organic polysulfides contain almost 100% trisulfides. In some embodiments, the molar ratios of S-2:S-3:S-4 polysulfides are from about 10-30:50-80:10-30. In certain embodiments, the S-3 enriched organic polysulfides have hydrocarbyl groups each independently having from about 2 to about 30 carbons or from about 2 to about 20 carbons, or from about 2 to about 12 carbons or from about 3 to about 6 carbons. The hydrocarbyl groups can be aromatic or aliphatic, but are preferably aliphatic. In certain embodiments, the hydrocarbyl groups are alkyl groups. In one embodiment, the S-3 enriched organic polysulfides comprise at least 60% dihydrocarbyl trisulfide. In other embodiments, the organic polysulfides by weight % of the total polysulfides are from about 5 wt % to about 20 weight % S-2; from about 30 wt % to about 80 wt % S-3, and from about 5 wt % to about 50 wt % S-4. Examples of suitable S-3 enriched organic polysulfides include those disclosed in U.S. Pat. No. 6,642,187, U.S. Pat. No. 6,689,723, or U.S. Pat. No. 6,489,271.

Friction Modifiers

The lubricating oil compositions herein may also optionally contain one or more additional friction modifiers. Suitable friction modifiers may comprise metal containing and metal-free friction modifiers and may include, but are not limited to, imidazolines, amides, amines, succinimides, alkoxylated amines, alkoxylated ether amines, amine oxides, amidoamines, nitriles, betaines, quaternary amines, imines, amine salts, amino guanidines, alkanolamides, phosphonates, metal-containing compounds, glycerol esters, sulfurized fatty compounds and olefins, sunflower oil and other naturally occurring plant or animal oils, dicarboxylic acid esters, esters or partial esters of a polyol and one or more aliphatic or aromatic carboxylic acids, and the like.

Suitable friction modifiers may contain hydrocarbyl groups that are selected from straight chain, branched chain, or aromatic hydrocarbyl groups or mixtures thereof, and may be saturated or unsaturated. The hydrocarbyl groups may be composed of carbon and hydrogen or hetero atoms such as sulfur or oxygen. The hydrocarbyl groups may range from about 12 to about 25 carbon atoms. In a embodiments the friction modifier may be a long chain fatty acid ester. In an embodiment the long chain fatty acid ester may be a mono-ester, or a di-ester, or a (tri)glyceride. The friction modifier may be a long chain fatty amide, a long chain fatty ester, a long chain fatty epoxide derivative, or a long chain imidazoline.

Other suitable friction modifiers may include organic, ashless (metal-free), nitrogen-free organic friction modifiers. Such friction modifiers may include esters formed by reacting carboxylic acids and anhydrides with alkanols and generally include a polar terminal group (e.g. carboxyl or hydroxyl) covalently bonded to an oleophilic hydrocarbon chain. An example of an organic ashless nitrogen-free friction modifier is known generally as glycerol monooleate (GMO) which may contain mono-, di-, and tri-esters of oleic acid. Other suitable friction modifiers are described in U.S. Pat. No. 6,723,685.

Aminic friction modifiers may include amines or polyamines. Such compounds can have hydrocarbyl groups that are linear, either saturated or unsaturated, or a mixture thereof and may contain from about 12 to about 25 carbon atoms. Further examples of suitable friction modifiers include alkoxylated amines and alkoxylated ether amines. Such compounds may have hydrocarbyl groups that are linear, either saturated, unsaturated, or a mixture thereof. They may contain from about 12 to about 25 carbon atoms. Examples include ethoxylated amines and ethoxylated ether amines.

The amines and amides may be used as such or in the form of an adduct or reaction product with a boron compound such as a boric oxide, boron halide, metaborate, boric acid or a mono-, di- or tri-alkyl borate. Other suitable friction modifiers are described in U.S. Pat. No. 6,300,291.

A friction modifier may be present in amounts of about 0 wt. % to about 10 wt. %, or about 0.01 wt. % to about 8 wt. %, or about 0.1 wt. % to about 4 wt. %, based on the total weight of the lubricant composition.

Viscosity Index Improvers

The lubricating oil compositions herein also may optionally contain one or more viscosity index improvers. Suitable viscosity index improvers may include polyolefins, olefin copolymers, ethylene/propylene copolymers, polyisobutenes, hydrogenated styrene-isoprene polymers, styrene/maleic ester copolymers, hydrogenated styrene/butadiene copolymers, hydrogenated isoprene polymers, alpha-olefin maleic anhydride copolymers, polymethacrylates, polyacrylates, polyalkyl styrenes, hydrogenated alkenyl aryl conjugated diene copolymers, or mixtures thereof. Viscosity index improvers may include star polymers and suitable examples are described in US Publication No. 2012/0101017 A1.

The lubricating oil compositions herein also may optionally contain one or more dispersant viscosity index improvers in addition to a viscosity index improver or in lieu of a viscosity index improver. Suitable dispersant viscosity index improvers may include functionalized polyolefins, for example, ethylene-propylene copolymers that have been functionalized with the reaction product of an acylating agent (such as maleic anhydride) and an amine; polymethacrylates functionalized with an amine, or esterified maleic anhydride-styrene copolymers reacted with an amine.

The total amount of viscosity index improver and/or dispersant viscosity index improver may be about 0 wt. % to about 20 wt. %, about 0.1 wt. % to about 15 wt. %, about 0.1 wt. % to about 12 wt. %, or about 0.5 wt. % to about 10 wt. % based on the total weight, of the lubricating composition.

Effective amounts of the various additive components for a specific formulation may be readily ascertained, but for illustrative purposes these general guides for representative effective amounts are provided. The amounts below are given in weight % of the finished fluid.

Example Ranges Example Ranges Component (wt %) (wt %) A compound of formula (I) 0-10  0.3-5 Dispersant 0-20  0.5-8 Extreme Pressure Agent 0-5   2-4 Rust Inhibitor  0-1.0  0.05-1.0 Corrosion Inhibitor 0-5  0.05-3  Demulsifier 0-5  0.005-1.0 Antifoam Agent  0-0.5 0.001-0.1 Diluent 0-10  1.0-5.0 Lubricating Base Oil Balance Balance

The compounds of the present invention, and lubricant additive compositions comprising the same, can be used in automotive gear or axle oils. Typical of such oils are automotive spiral-bevel and worm-gear axle oils which operate under extreme pressures, load and temperature conditions, hypoid gear oils operating under both high speed, low-torque and low-speed, high torque conditions.

Industrial lubrication applications in which the compounds of the present invention, and lubricant additive compositions comprising the same, can be used include hydraulic oils, industrial gear oils, slideway machines oils, circulation oils and steam turbine oils, gas turbine oils, for heavy-duty gas turbines and aircraft gas turbines, way lubricants, gear oils, compressor oils, mist oils and machine tool lubricants. Engine oils are also contemplated such as passenger car motor oils, heavy duty diesel engine oils, marine engine oils, locomotives, and high speed automotive diesel engines.

Functional fluids can also be prepared from the compounds of the present invention and lubricant additive compositions comprising the same. These fluids include automotive fluids such as manual transmission fluids, automatic transmission fluids, continuously variable transmission fluids, power steering fluids and power brake fluids.

Compounds of the present invention can also be incorporated into greases such as automotive, industrial and aviation greases, and automobile chassis lubricants.

The invention also provides a method of lubricating metal surfaces. Lubricating metal surfaces with lubricant compositions of the present invention can reduce wear between the metal surfaces when moving. In one embodiment, the metal surfaces being lubricated can be a machine part. The machine part can comprise an axle, a differential, an engine, a manual transmission, an automatic transmission, a continuously variable transmission, a crankshaft, a clutch, a hydraulic apparatus, an industrial gear, a slideway apparatus, and a turbine.

The invention further provides for a method of lubricating a driveline, industrial, or metalworking device comprising lubricating the driveline, industrial or metalworking device with a lubricant composition comprising a compound of the present invention.

Seals

Seals are used in the design and manufacture of a multitude of machines including engines, gear assemblies and transmissions to maintain the fluid or lubricant within the apparatus. Machine failures are not caused only by surface fatigue but also because of lubrication issues. Thus, seals play a critical role in decreasing loss of lubrication, reducing contaminant ingress, and increasing equipment runtime. The seals come in contact with the lubricant and can, under certain operating conditions, lose their elasticity and become brittle. Often the rate of deterioration of the seals is affected by the additives present in the lubricant. Seals are typically made of polymeric materials including nitrile rubber, silicone, ethylene acrylate, fluoroelastomers and polyacrylates. Extending the functional life of elastomeric seals can decrease machine wear and downtime, thus increasing productivity and machine lifetime. The present invention provides methods for extending the functional life of elastomeric seals that contact a lubricating or functional fluid composition, the method comprising contacting the seal with an effective amount of a lubricating composition of the present invention. Standard testing of seals is well known in the art for both static and dynamic wear and durability. Standard testing methodologies are readily ascertainable by the skilled artisan.

Although certain embodiments of the present invention may be described individually herein, it is understood by the skilled artisan that any one embodiment can be combined with any other embodiment or embodiments, and such combinations are within the scope of the instant invention.

Synthetic Schemes

Certain compounds of the present invention can be prepared using the following generic schemes:

In certain instances, the synthesis of compounds can result in the production of positional isomers. For example, both primary and secondary alcohols can be formed by a single reaction as follows:

Compounds prepared by the methods illustrated in schemes 2 and 3 can be prepared to enrich certain reaction products. However, in certain embodiments, the reaction products are a mixture of products. For example, the reaction product of the methods described in scheme 2 may be a mixture of the P2a and the P3a product. Similarly, the reaction product from scheme 3 can be a mixture of one or more of the P5a, P6a and P7a product. Likewise, some amount of the reactants may be present in the reaction product. The skilled artisan can readily ascertain the compounds produced from these methods and the mixtures that can result. In the event that a single reaction product is desired, the skilled artisan can employ routine and conventional methods for purifying such reaction products. Purified products and mixtures that result from methods such as those described above are within the scope of the present invention.

The structures shown in the Intermediates and Examples below are the structures of the most abundant isomers produced in the particular reactions described. The skilled artisan appreciates and understands that the above epoxide addition reaction and reactions similar thereto produce compounds as secondary alcohols (P1a). However, the same epoxide addition reaction can form some amount of primary alcohols (P1b). Therefore, the resulting product of the epoxide addition reactions can be a mixture of positional isomers. For the sake of simplicity, only the secondary alcohols and the reaction products therefrom are shown below in Intermediates and Examples. However, all positional isomers of the Intermediates and Examples are within the scope of the invention as a result of these types of reactions.

INTERMEDIATES AND EXAMPLES

The presence of all Intermediates and Examples can be confirmed by 31P NMR, and was confirmed where indicated.

Intermediates

Synthesis of Intermediate P1-A: O,O-bis(4-methylpentan-2-yl) S-hydrogen phosphorodithioate (75.34 g or 0.25 mol) is heated to 40° C. and propylene oxide (14.65 g or 0.25 mol) is added slowly so as to keep the reaction temperature below 50° C. The reaction mixture is then cooked at 50° C. for 30 minutes. Intermediate P1-A is the reaction product and was confirmed by 31P NMR.

Synthesis of Intermediate P1-B: P1-B can be made in a process similar to P1-A except O,O-bis(4-methylpentan-2-yl) S-hydrogen phosphorodithioate is replaced with O,O-bis(isopropyl) S-hydrogen phosphorodithioate. Intermediate P1-B is the reaction product.

Synthesis of Intermediate P1-C: P1-C can be made in a process similar to P1-A except O,O-bis(4-methylpentan-2-yl) S-hydrogen phosphorodithioate is replaced with O,O-bis(2-ethylhexyl) S-hydrogen phosphorodithioate. Intermediate P1-C is the reaction product.

Synthesis of Intermediate P1-D: P1-D can be made in a process similar to P1-A except O,O-bis(4-methylpentan-2-yl) S-hydrogen phosphorodithioate is replaced with O,O-bis(isobutyl) S-hydrogen phosphorodithioate. Intermediate P1-D is the reaction product.

Synthesis of Intermediate P3-A: P1-A (600 g, 1.68 moles) was combined with O,O-di-isopropyl dithiophosphoric acid (180 g, 0.84 moles; used as supplied by Cheminova) in a round bottomed flask equipped with a magnetic stirring bar. The reaction contents were heated to 90° C. under reduced pressure (10 mm Hg). Throughout the reaction isopropanol was distilled off and collected into a separate cooled vessel. After 6.5 hours the reaction contents were cooled to 10° C. and propylene oxide (49 g, 0.84 moles; Sigma Aldrich) slowly added to the stirring reaction over a 45 minute period. The presence of P3-A was confirmed by 31P NMR.

Synthesis of Intermediates P3-B, P3-C and P3-D: P3-B, P3-C and P3-D can be prepared similarly to P3-A, with the exception that P1-A is replaced with P1-B, P1-C and P1-D, respectively.

Synthesis of Intermediate P4-A: Intermediate P3-A is prepared as above. To the reaction, O,O-di-isopropyl dithiophosphoric acid (376 g, 1.76 moles; used as supplied by Cheminova) was added and the reaction mixture heated at 90° C. and 10 mm Hg of pressure for 6 hours before cooling to room temperature. The presence of P4-A was confirmed by 31P NMR.

Synthesis of Intermediates P4-B, P4-C and P4-D: P4-B, P4-C and P4-D can be made similarly to P4-A, with the exception that P3-A is replaced with P3-B, P3-C and P3-D, respectively.

Synthesis of intermediate P7-A: P3-A (345 g, 0.4 moles) was combined with 0,0-di-isopropyl dithiophosphoric acid (43 g, 0.2 moles; used as supplied by Cheminova) and the reaction mixture heated at 90° C. and 10 mm Hg of pressure for 6 hours before cooling to room temperature. The presence of P7-A was confirmed by 31P NMR.

Synthesis of intermediates P7-B, P7-C and P7-D: P7-B, P7-C and P7-D can be prepared similarly to P7-A, with the exception that P3-A is replaced with P3-B, P3-C and P3-D, respectively.

EXAMPLES Example 1

Intermediate P1-A (600 g, 1.68 moles) was combined with O,O-di-isopropyl dithiophosphoric acid (180 g, 0.84 moles; used as supplied by Cheminova) in a round bottomed flask equipped with a magnetic stirring bar. The reaction contents were heated to 90° C. under reduced pressure (10 mm Hg). Throughout the reaction isopropanol was distilled off and collected into a separate cooled vessel. After 6.5 hours the reaction contents were cooled to 10° C. and propylene oxide (49 g, 0.84 moles; Sigma Aldrich) slowly added to the stirring reaction over a 45 minute period. At this time O,O-di-isopropyl dithiophosphoric acid (376 g, 1.76 moles; used as supplied by Cheminova) was added and the reaction mixture heated at 90° C. and 10 mm Hg of pressure for 6 hours before cooling to room temperature. Ethyl acrylate (270 g, 2.7 moles; Dow Chemical) was next added to the reaction and the temperature brought to 70° C. for 2 hours. Subsequently, the reaction was brought to 80° C. and a 100 mm Hg vacuum applied until ethyl acrylate no longer distilled off into the cold trap. The presence of Example 1 was confirmed by 31P NMR.

Example 2

Intermediate P3-A (345 g, 0.4 moles) was combined with O,O-di-isopropyl dithiophosphoric acid (43 g, 0.2 moles; used as supplied by Cheminova) and the reaction mixture heated at 90° C. and 10 mm Hg of pressure for 6 hours before cooling to room temperature. Ethyl acrylate (20 g, 0.2 moles; Dow Chemical) was next added to the reaction and the temperature brought to 70° C. for 2 hours. Subsequently, the reaction was brought to 80° C. and a 100 mm Hg vacuum applied until ethyl acrylate no longer distilled off into the cold trap. The presence of Example 2 was confirmed by 31P NMR.

Example 3

Intermediate P4-A (200 g, 0.2 moles) was combined with acrylic acid (14 g, 0.19 moles) and the reaction left to stir at 70° C. for two hours before applying a 10 mm Hg vacuum to strip off any remaining volatiles. The presence of Example 3 was confirmed by 31P NMR.

Example 4

Intermediate P7-A (200 g, 0.11 moles) was combined with acrylic acid (7.2 g, 0.1 moles) and the reaction left to stir at 70° C. for two hours before applying a 10 mm Hg vacuum to strip off any remaining volatiles. The presence of Example 4 was confirmed by 31P NMR.

Example 5

The compound of Example 5 is prepared as in Example 3 except P4-A is replaced with P4-B.

Example 6

The compound of Example 6 is prepared as in Example 4 except P7-A is replaced with P7-B.

Example 7

The compound of Example 7 is prepared as in Example 1 except P1-A is replaced with P1-B.

Example 8

The compound of Example 8 is prepared as in Example 2 except P3-A is replaced with P3-B.

Example 9

The compound of Example 9 is prepared as in Example 3 except P4-A is replaced with P4-C

Example 10

The compound of Example 10 is prepared as in Example 4 except P7-A is replaced with P7-C.

Example 11

The compound of Example 11 is prepared as in Example 1 except P1-A is replaced with P1-C.

Example 12

The compound of Example 12 is prepared as in Example 2 except P3-A is replaced with P3-C.

Example 13

The compound of Example 13 is prepared as in Example 3 except P4-A is replaced with P4-D

Example 14

The compound of Example 14 is prepared as in Example 4 except P7-A is replaced with P7-D.

Example 15

The compound of Example 15 is prepared as in Example 1 except P1-A is replaced with P1-D.

Example 16

The compound of Example 16 is prepared as in Example 2 except P3-A is replaced with P3-D.

Example 17

Example 17 is prepared as in Example 1 except the ethyl acrylate is replaced with methyl acrylate.

Example 18

Example 18 is prepared as in Example 2 except the ethyl acrylate is replaced with methyl acrylate.

Example 19

Example 19 is prepared as in Example 7 except the ethyl acrylate is replaced with methyl acrylate.

Example 20

Example 20 is prepared as in Example 8 except the ethyl acrylate is replaced with methyl acrylate.

Example 21

Example 21 is prepared as in Example 11 except the ethyl acrylate is replaced with methyl acrylate.

Example 22

Example 23

Example 23 is prepared as in Example 15 except the ethyl acrylate is replaced with methyl acrylate.

Example 24

Example 24 is prepared as in Example 16 except the ethyl acrylate is replaced with methyl acrylate.

Example 25. Amine Carboxylate Salt

The compound of Example 3 can be treated with an amine containing compound, for example octylamine or oleylamine, at such a treat rate that TAN=TBN to produce an amine carboxylate salt. The compound of Example 3 can be added to a suitable reaction vessel under stirring. To this the amine containing compound can be added slowly so as to control the exothermic event.

Anti-Wear Performance

Compounds were tested in the four ball wear scar and high temperature L37 tests to determine anti-wear performance. Compounds were individually blended into finished fluids such that a constant level of phosphorous (1100 ppm) was maintained throughout the series. Other than the test compounds, each of the fluids contained a common group of additives employed at equal treat rates. Shown in Table 1 is a summary of the high temperature L37 performance data obtained on these fluids. It can be seen that the ashless dithiophosphate failed the wear test and had end of test iron levels (EOT Fe), as measured by ICP on the used oil, in excess of 5000 ppm. Conversely, compounds of the instant invention, particularly Examples 1 through 4, provide sufficient protection to the gear surfaces that passing test ratings are achieved.

TABLE 1 Summary of High Temperature L37 Wear Performance Data. Fluid HT-L37 EOT Fe, Ring Pinion Compound Code Result ppm Ratings Ratings ashless — Fail 5880 5/8/6 6/8/6 dithiophosphate* Ex. 1 R1414317T Pass 122 8/10/10 8/9/8 Ex. 2 R1414444T Pass 127 8/10/10 7/8/8 Ex. 3 R14 14318T Pass 133 8/10/10 8/9/9 Ex. 4 R14 14487T Pass 130 8/10/10 8/9/8 *Commercially available as Irgalube 63, typically containing 19.8% sulfur and 8.9% phosphorus, from BASF

The samples above were subjected to the High Temperature L-37 test (according to ASTM D-6121), modified to test the lubricant at 325° F. The HT L-37 is used to determine the load-carrying, wear, and extreme pressure characteristics of gear lubricants in hypoid axle assemblies under conditions of high-speed, low-torque, and low-speed, high-torque operation. The procedure's apparatus includes a rear axle assembly, an engine, a transmission, and two large dynamometers. The axle is operated for 100 minutes at 440 axle rpm, 295° F. lubricant temperature, and 9460 lb-in. of torque. The axle is then operated for 16 hours at 80 axle rpm, 325° F. lubricant temperature, and 41,800 lb-in. of torque. The pass/fail criteria require that there be no “significant” distress to the ring and pinion gears in several different wear categories, including wear, rippling, ridging, spalling and scoring.

In Table 1 above, test results for formulations containing Examples 1, 2, 3 and 4 show that the gear distress as measured in the HT-L37 test was identified by a “pass” test result. A “pass” indicates that significant gear distress was not observed at the end of test. Thus, there was not a significant amount of iron detected in the test sample after completion of the test. When iron is present in the end of test fluid in significant amounts, it is evidence of gear distress and loss of anti-wear protection. All finished fluids used for HT-L37 testing contained sufficient anti-wear to deliver 1100 ppm phosphorus to the finished fluid. The finished fluids only differed in the antiwear component present, but otherwise contained identical formulations of typical axle componentry and base stock. The formulations for the HT-L-37 testing contained 3.24% sulfurized isobutylene, 1.4% of a pour point depressant, 1% boronated maleated bis-succinimide dispersant made with 1300 MW polyisobutylene, 0.15% 2,5-(t-nonylthio)-1,3,4-thiadiazole, 0.05% antifoam, 0.005% dimer acid, 1.15% antiwear compound of the present invention, and the balance was a base oil mixture of 150N and 2500N from ExxonMobil in a 35:54 ratio. The 150N has a kinematic viscosity at 40° C. of 29-32 m²/sec. And the 2500N has a kinematic viscosity at 100° C. of 30.6-32.7 mm²/sec. The finished fluid including the base oils and the additive components had a kinematic viscosity at 100° C. of 15.5 cSt.

Extending Functional Life of Seals

Standardized radial shaft seal testing is carried out using 75FKM595 fluoroelastomer seal material (Freudenberg Sealing Technologies GmbH & Co. KG, Weinheim, Germany). Briefly, a radial seal is tested on an 85 mm shaft which rotates at 3000 rpm for ten 24-hour cycles consisting of 20 hours at 120° C. followed by 4 hours of cool down at room temperature for total of 240 hours. At the end of the test, seals are evaluated for leakage, sealing time, carbon deposits, contact discoloration, cracking, blistering, chemical attack and a circumferential groove.

Standardized static seal testing is carried out using two different seal materials. Nitrile seal material (NBR 28 from Freudenberg Sealing Technologies GmbH & Co. KG, Weinheim, Germany) was tested at 100° C. Fluoroelastomer seal material (AK6 from Freudenberg Sealing Technologies GmbH & Co. KG, Weinheim, Germany) was tested at 150° C. Each seal material is exposed to the test lubricant compositions for 168 hours at the temperatures specified. At the end of the test, seals are evaluated for changes in tensile strength, elongation modulus, hardness, and volume.

Radial shaft seal testing was carried out on lubricant compositions of the present invention including various types of detergents as described in Table 2. All formulations contain 93.5% synthetic 75W90 base oil system and a component blend of 1.0 wt % succinimide dispersant, 0.5 wt % antioxidant, 0.125 wt % copper corrosion inhibitor, 0.05 wt % antifoam 2.9 wt % organic polysulfide and 0.305 diluent oil. All components are in wt % of complete formulation.

TABLE 2 Formulations A B C D E overbased Mg sulfonate 0.5 detergent overbased Ca Phenate 0.5 detergent overbased Mg 0.5 salicylate/sulfonate detergent overbased Ca Sulfonate 0.5 detergent neutral Ca Sulfonate 0.5 detergent Example 1 1.12 1.12 1.12 1.12 1.12 Radial Seal Test pass borderline borderline pass fail

The results above demonstrate that sulfonate and phenate detergents provide better radial seal performance as compared to salicylate containing detergents in combination with compounds of formula I.

Lubricant compositions comprising overbased Mg sulfonate detergents were further tested in the dynamic and static seal tests as described in Table 3 in the presence of S-3 enriched polysulfides versus non-S-3 enriched polysulfides such as sulfurized isobutylene. All formulations contain 91% synthetic base oil system and a component blend of 1.5 wt % succinimide dispersant, 0.5 wt % antioxidant, 0.2% overbased Mg sulfonate detergent, 0.12 wt % copper corrosion inhibitor, 0.05 wt % antifoam and 0.39 wt % rust inhibitor. All components are in wt % of complete formulation.

TABLE 3 Formulations F G H J Diluent oil 0.98 0.74 1.86 1.62 S-3 enriched polysulfide 3 3 Sulfurized isobutylene 3.25 3.25 Thiophosphate antiwear 2.25 2.25 0.25 0.25 Example 1 1.12 1.12 Radial seal test pass pass pass pass Fluoroelastomer static seals Change tensile strength −34.5 −34.5 −16.2 −15.5 Change elongation at rupture (%) −18.9 −33.6 2.1 0.7 Nitrile static seals Change tensile strength −18.1 −44.7 −16.6 −48.7 Change elongation at rupture (%) −39.4 −68.7 −41.2 −69.9

The results above demonstrate that S-3 enriched polysulfides in combination with the compounds of formula I provide improved elongation and tensile strength in static seal tests for both fluoroelasomeric and nitrile seals as compared to the same formulations with only the thiophosphate antiwear.

Other embodiments of the present disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the embodiments disclosed and suggested herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims. 

The invention claimed is:
 1. A compound of formula (I)

or a tribologically acceptable salt thereof, wherein A is:

each R¹ is the same or different and is independently selected from alkyl; each R² and R³ are independently selected from H and alkyl; Y is —R⁴—R⁵—R⁶; R⁴ is alkylene; R⁵ is —C(O)—; R⁶ is selected from the group consisting of alkyl and hydroxy; m is an integer from 2 to 8; X₁ is R⁸ or Z; X₂ is selected from the group consisting of R⁸,

R⁸ is alkyl; and Z is

wherein when X₂ is R⁸, X₁ is Z.
 2. The compound of claim 1, wherein each R¹ is C₁-C₁₀alkyl.
 3. The compound of claim 1, wherein m is
 2. 4. The compound of claim 1, wherein R² is C₁-C₁₀alkyl.
 5. The compound of claim 1, wherein R³ is H.
 6. The compound of claim 1, wherein R¹ is C₃-C₁₀alkyl, m is 2, R² is C₁-C₁₀alkyl, and R³ is H.
 7. The compound of claim 1, wherein the compound is selected from:


8. A lubricant additive composition comprising one or more compounds of claim
 7. 9. A lubricant additive composition comprising one or more compounds of claim
 1. 10. The lubricant additive composition of claim 9, wherein the composition further comprises a sulfonate or a phenate detergent.
 11. The lubricant additive composition of claim 10, wherein the detergent is an overbased magnesium sulfonate detergent.
 12. The lubricant additive composition of claim 10, wherein the detergent is an overbased calcium phenate detergent.
 13. The lubricant additive composition of claim 10, wherein the detergent is selected from an overbased calcium sulfonate detergent and a neutral calcium sulfonate detergent.
 14. The lubricant additive composition of claim 10, wherein the lubricant additive composition further comprises one or more additive components selected from the group consisting of an antioxidant, antiwear agent, corrosion inhibitor, extreme pressure agent, dispersant, viscosity index improver, and friction modifier.
 15. The lubricant additive composition of claim 14, wherein an extreme pressure agent is an organic polysulfide.
 16. The lubricant additive composition of claim 15, wherein the polysulfide is an S3-enriched organic polysulfide.
 17. A lubricant composition comprising: a) a base oil or a grease prepared therefrom; and b) the lubricant additive composition of claim 8, wherein the base oil is a major amount of the composition.
 18. A lubricant composition comprising: a) a base oil or a grease prepared therefrom; and b) the lubricant additive composition of claim 9, wherein the base oil is a major amount of the composition.
 19. A method of lubricating moving metal surfaces comprising lubricating the metal surfaces with a lubricant composition of claim
 17. 20. A method of lubricating moving metal surfaces comprising lubricating the metal surfaces with a lubricant composition of claim
 18. 